1. Field of the Invention
The present invention generally relates to electric submersible pumps (ESP), or other pumps, for downhole use in high temperature environments.
2. Background Art
In oil wells and the like from which the production of fluids is desired, a variety of fluid lifting systems have been used to pump the fluids to surface holding and processing facilities. One such pumping system is a submersible pumping assembly which is immersed in the fluids in the wellbore. A submersible pumping assembly typically comprises a pump and a motor. The motor drives the pump to pressurize and pass the fluid through production tubing to a surface location. The motor is typically driven by electric power. Such a pump is referred to as an electric submersible pump assembly (ESP).
FIG. 1 shows an ESP assembly 10, which is disposed in a wellbore 12 and suspended therein via a tubing 14 extending from the surface 16. The ESP assembly 10 may have, from bottom to top, an electric submersible motor 18, a seal section assembly 20, and a pump 22. The pump 22 may include an intake pump section 24 and a pump discharge head 26 that move a production stream 28 through production tubing 14 to the surface 16.
The motor 18 may be controlled at the surface by a switch board 34 with an optional variable speed device (VSD) via a cable 36, as one skilled in the art would be aware, a packer 38 may be used to isolate the production zone and to protect casing 40. The casing 40 may have casing perforations 42, which may allow reservoir production 44 to flow into the wellbore 12.
With the wells being drilled deeper and deeper, there is an increasing need to have ESPs that can withstand more and more harsh environments, such as higher temperatures and higher pressures. Therefore, ESP systems that can withstand high temperature are needed.